Who wants to talk about RV holding tanks? We do! There are four basic things you need to know when it comes to your RV’s gray and black holding tanks. This article will help you to understand them better.

For starters

This is probably pretty obvious, but your RV has three types of holding tanks:

Fresh water tank: This holding tank holds clean, potable water from your home or an RV park’s fresh water supply. This is used for drinking, cooking, taking showers or baths, and even to use when flushing down solids in your toilet.

Gray water tank: These holding tanks (some RVs have more than one) contains water from your kitchen or galley sink, shower or bathtub, and, sometimes, sinks in bathrooms (though some RVs have this drain into the black tank as well).

Black water tank: In these holding tanks goes everything from your toilet. We’ll just leave it at that!

Priming the system: What’s a holding tank?

Here’s the first “pro tip” for you: When you arrive at your next RV park, resort or site, add a couple of gallons of fresh water into all of your tanks. That’s assuming you are going to be dumping where you are staying. Two or three gallons down the toilet, galley sink, and tub or shower will prepare your holding tanks will help to keep them at the critical 50/50 minimum ratio of waste/water and will help keep your holding tanks lubricated when solids enter (even food particles will suspend better in some liquid).

Chemicals and additives in your holding tanks

You don’t need them! The best waste system is emptied every two or three days — or when the tank is 3/4ths or more full. Adding enzymes, chemicals, priobiotics, or anything to break down the waste in your holding tanks will only create a sticky, pancake batter-like mess that will be harder to get out later.

Dumping your holding tanks

We all know the process. Black first, then gray. But do you know you should “top off” all of your tanks prior to dumping with some fresh, clean water? Dumping your tanks when they are full is the best way to create the “down pressure tornado” of water that will pull waste from corners of your holding tank and drive debris and solids out quickly and thoroughly. Another “pro tip” is to keep your black tank rinse system on while dumping that tank. A bit of higher pressure spraying in that tank can also help drive out waste.

Flushing your holding tanks

“Flushing?,” you ask. “Doesn’t my black holding tank flush system do that?” Somewhat, but not nearly good enough to keep your holding tanks clean and working properly. Plus almost no RV has this type of system for their gray holding tanks. To keep everything working — and keep those holding tank sensors working! — use something like the Valterra Backflush valve as the last step in your holding tank emptying process. Backflushing two or three times for your black holding tanks and once or twice for your gray holding tanks will keep everything working well, smelling nice, and functioning properly.

Cleaning those holding tanks

Wait, you thought you just cleaned your holding tanks, right? Sort of. But there’s no way you can match the scrubbing and flushing process that All Pro Water Flow dealers like Kleen Tank can. With our special equipment, training and processes, we’re able to get your holding tanks as clean as they were when they came from the factory. Plus, in most cases, we can get inaccurate holding tank sensors working again!